OFFSET
0,3
FORMULA
a(0) = 1; a(n) = Sum_{k=1..n} (-1)^floor((k-1)/2) * k * binomial(n-1,k-1) * a(n-k).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x)^(cos(x)+sin(x))))
(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (-1)^((j-1)\2)*j*binomial(i-1, j-1)*v[i-j+1])); v;
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 18 2022
STATUS
approved